1. Field of the Invention
This application relates to the field of speed-responsive engaging devices for hydrodynamic devices.
2. Prior Art
It is known in the prior art to provide lock-up clutches for hydrodynamic devices. More particularly, copending application, Ser. No. 732,265, filed Oct. 14, 1976 of common assignee provides a clutch mechanism for hydrodynamic devices having a shoe assembly having a roller therein and engaged by centrifugal force and, in addition, engaged by the wedging effect of a cam surface on the roller mechanism and such clutch devices lock together the impeller and turbine elements to improve efficiency by eliminating slippage. It has been recognized that the structures of the aforementioned applications as well as the device to be described herein provide a solution to the problem of lock-up clutches to provide a lock-up clutch which disengages during torque impulses or torque reversals to provide smooth, shockless operation and eliminate torsional vibrations.
These previous solutions to the torque converter clutch problem, although workable and dramatic improvements over those known prior, can operate in certain environments wherein the self-energizing effect of the cam and roller is so great that the shoes can be resistant to coming out of engagement at the proper time. Typically, self-energizing clutches need a simple and economical way of control so that they will engage and disengage at the proper time.